Scientists explain evolution of some of the largest dinosaurs

March 29, 2016

A Giraffatitan model of a Sauropod. Credit: Dr Peter L Falkingham /Liverpool John Moores University

Scientists from the University of Liverpool have developed computer models of the bodies of sauropod dinosaurs to examine the evolution of their body shape.

Sauropod dinosaurs include the largest land animals to have ever lived. Some of the more well-known sauropods include Diplodocus, Apatosaurus and Brontosaurus. They are renowned for their extremely long necks, long tails as well as four thick, pillar-like legs and small heads in relation to their body.

To date, however, there have been only limited attempts to examine how this unique body-plan evolved and how it might be related to their gigantic body size. Dr Karl Bates from the University's Department of Musculoskeletal Biology and his colleagues used three-dimensional computer models reconstructing the bodies of sauropod dinosaurs to analyse how their size, shape and weight-distribution evolved over time.

Evolutionary history

Dr Bates found evidence that changes in body shape coincided with major events in sauropod evolutionary history such as the rise of the titanosaurs. The early dinosaurs that sauropods evolved from were small and walked on two legs, with long tails, small chests and small forelimbs. The team estimate that this body shape concentrated their weight close to the hip joint, which would have helped them balance while walking bipedally on their hind legs.

As sauropods evolved they gradually altered both their size and shape from this ancestral template, becoming not only significantly larger and heavier, but also gaining a proportionally larger chest, forelimbs and in particular a dramatically larger neck.

The team's findings show that these changes altered sauropods' weight distribution as they grew in size, gradually shifting from being tail-heavy, two-legged animals to being front-heavy, four-legged animals, such as the large, fully quadrupedal Jurassic sauropods Diplodocus and Apatosaurus.

The team found that these linked trends in size, body shape and weight distribution did not end with the evolution of fully quadrupedal sauropods. In the Cretaceous period - the last of the three ages of the dinosaurs - many earlier sauropod groups dwindled. In their place, a new and extremely large type of sauropod known as titanosaurs evolved, including the truly massive Argentinosaurus and Dreadnoughtus, among the largest known animals ever to have lived.

Front heavy

The team's computer models suggest that in addition to their size, the titanosaurs evolved the most extreme 'front heavy' body shape of all sauropods, as a result of their extremely long necks.

Dr Bates said: "As a result of devising these models we were able to ascertain that the relative size of sauropods' necks increased gradually over time, leading to animals that were increasingly more front-heavy relative to their ancestors."

Dr Philip Mannion from Imperial College London, a collaborator in the research, added: "These innovations in body shape might have been key to the success of titanosaurs, which were the only sauropod dinosaurs to survive until the end-Cretaceous mass extinction, 66 million years ago."

Dr Vivian Allen from the Royal Veterinary College London, who also collaborated in the research, added: "What's important to remember about studies like this is that there is a very high degree of uncertainty about exactly how these animals were put together. While we have good skeletons for many of them, it's difficult to be sure how much meat there was around each of the bones. We have built this uncertainly into our models, ranging each body part from emaciated to borderline obesity, and even using these extremes we still find these solid, trending changes in body proportions over sauropod evolution."

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10 comments

True scientists will look at this data and say, "there have been some very big dinosours in the past". Bogus scientists who have nothing to base their opinion on will add, "and this evolved from some smaller form".

@barta delusional fundamental religious fanatic will look at your post and say: "there is merit in his argument"

anyone with an education, being even only semi-literate in evidence based anything (especially science) or holding some necessity for logical thought will look at your comment and state:"since bart made a false claim that has absolutely no evidence it can be dismissed as having the same validity as used toilet paper"

True scientists will look at this data and say, "there have been some very big dinosours in the past". Bogus scientists who have nothing to base their opinion on will add, "and this evolved from some smaller form".

True scientists will look at this data and say, "there have been some very big dinosours in the past". Bogus scientists who have nothing to base their opinion on will add, "and this evolved from some smaller form".

Just because you don't understand something doesn't mean it's wrong. Remember that 100% of all scientists are way smarter than you.

Scientist must explain first how can separate multi celled organism in two diferent genders in time period of one generation to be passible next generation, which require complex functionality connected with hundred genes and their control mechanims in DNA and this functinality must be fully compatible in both genders. Can blind chance to quess that the mother will have to give birth a few months later and to prepare his body for birth which is connected with big physiological changes?Can the chance guess that the mother will bare the chidren and give birth a few months later and to prepare the body for birth toThey should answer to the question what is the mechanism for the emergence of new genes and functionality that is compatible with old functionality and why they still can not give example for positive effect of mutations.And how 100% negative effects of mutations can allaw the survival of the organisms billions of years and even their evolution.

@vikoTROLL1- can't you read, you moron?2- not all mutations are destructive3- see the second link above for not only proof of 2, but also as evidence for your argument from stupidity that i quoted

If destruction prebvail how teh process of evolutioncan be pasible

aaaand again, not all mutations are destructivejust repeating your lies doesn't mean they're truesee the second link in my above post which proves not only that there are beneficial mutations, but that you don't comprehend even a fraction of biology needed to argue against evolution

Answer to this question

learn to f*cking read. i did

Do not be distracted like a woman but be precise in your answers

you are the one who's tampon is too large to pull your own head out, girlie

perhaps you should try reading the above a few more times?

LMFAO

literacy isn't a part of your formal education where you live, is it?

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